Arsenic in drinking water is a proven cause of cancer, and continues to pose a significant human and environmental threat in the U.S and globally. Arsenic has been found in drinking water in forty-nine States and constitutes a major pollutant in many Superfund sites. This omnipresence requires adequate monitoring equipment that is not only fast, but also combines the sensitivity and performance of laboratory-grade equipment with the ease-of-use and mobility of test kits. OndaVia has developed an analytical platform using Surface-Enhanced Raman Spectroscopy (SERS) for trace chemical detection in water. This platform successfully demonstrated reliable detection of trace- levels of perchlorate at a California decontamination site. OndaVia proposes to adapt its inexpensive, field-deployable and robust solution for ultra-sensitive and rapid arsenic monitoring. This novel innovation, capable of speciation and quantitative arsenic measurement at ppb (parts per billion) levels in water, will help reduce arsenic exposure and advance the prevention for arsenic-induced illnesses. It will critically enhance early detection, help site-prioritization and decontamination efforts, improve testing capabilities of small- and medium-sized water systems, and assist policy makers fill gaps in water regulation. OndaVia's technology relies on an inexpensive microfluidic chip that embeds gold nanoparticles to form a robust, reliable and effective plasmonic enhancement substrate within a microchannel. In SERS, enhancements are obtained when the analytes interact or adhere to the surface of the plasmonic metal. To obtain single-digit ppb detection of arsenic, OndaVia proposes to embed a new generation of gold- nanoparticles specifically designed for arsenic detection. Funding will be used to synthesize, characterize, and optimize the innovative nanoparticles, build and calibrate the new substrate using lab-standards, and finally quantify and speciate arsenic in real-world water samples.